How to compare two directories using diff while ignoring non-existing files?

Question

I would like to use diff to compare two directories for differing files, using the -q option for brief output. However, the output is cluttered with a lot of files that only exist in one directory, but not the other. Can I force diff (or use another tool) to only show files that differ AND exist in both directories?

The current command I use is

diff -q <dir1> <dir2>

Any ideas are appreciated.

score 27 · Accepted Answer · answered Jul 04 '12 at 08:34

27

It prints a bunch of lines like

Only in dir1/blah: blah

right? So just throw them away with grep.

LC_ALL=C diff ... | grep -v '^Only in'

The LC_ALL=C is to make sure that the standard "Only in" message will be printed, not any translation.

answered Jul 04 '12 at 08:34

Alan Curry

14,255
3
32
33

No option to do this without grep? – zdm Jun 05 '22 at 05:25
This also filters valid differences starting with "Only in". – Graham Leggett Dec 07 '22 at 16:46

How to compare two directories using diff while ignoring non-existing files?

1 Answers1